SmartShunt 500A/50mV (IP21)
See where battery negative, the system's negative returns and the fused supply lead connect. Open the example to plan monitoring around your own batteries, chargers and loads.
Open this example as a new project. Use your own parts and cable lengths to make the plan yours.
The house-bank negative connects to the battery side of the shunt. Load and charging returns connect to the system side so their current passes through the shunt. The example shows the small fused supply lead separately.
The 500 A rating is the shunt's measuring range. Main cable sizes depend on the connected equipment, current and cable lengths; the measuring range does not select a cable or fuse.
Wiring diagram
Open this example in Crimp to use your own parts and cable lengths. Review the assumptions and installation notes as you adapt the circuit.
House bank +
positive connection
10 mm² (8 AWG) · 25 A fuse
3 m one way · 18 A design
To 18 A load +
30 A charger +
positive connection
10 mm² (8 AWG) · 40 A fuse
3 m one way · 30 A design
To House bank +
House bank −
negative connection
10 mm² (8 AWG) · unfused return
30 cm one way · 48 A design
To SmartShunt 500 BATT −
SmartShunt 500 LOAD −
negative connection
10 mm² (8 AWG) · unfused return
30 cm one way · 30 A design
To − Bus −
18 A load −
negative connection
10 mm² (8 AWG) · unfused return
3 m one way · 18 A design
To − Bus 1
30 A charger −
negative connection
10 mm² (8 AWG) · unfused return
3 m one way · 30 A design
To − Bus 2
House bank +
signal connection
Supplied lead · 1 A slow-blow fuse
1.5 m one way
To SmartShunt 500 B+ sense
Example allowances · ABYC E-11 sizing · verify actual protection
The 12 V example includes a 200 Ah placeholder bank, an 18 A load allowance, a 30 A charging allowance and a system-negative bus. Both returns pass through the shunt. The short shunt links are 0.3 m each; the supplied fused Vbatt+ lead is represented separately. Power-cable sizes come from the connected example, not the shunt's 500 A measuring range. Select and locate actual battery protection before building. Manufacturer installation manual
Edit this wiring exampleInstallation notes
Guidance for this model, with sources linked beside the relevant advice.
Verified against the manufacturer's documentation (rev. 19 — 08/2026), checked 2026-09-11. Manufacturer documentation →
This is the SmartShunt 500A/50mV, IP21, with Bluetooth and VE.Direct. It is the dry-location model, not the separately available IP65 version. The 500 A marking describes its measuring range; it does not specify the battery fuse or the current your installation will draw. Check the SmartShunt technical data against your unit.
Connect the house-bank negative only to BATTERY MINUS. Put the system's negative bus, including every load and charging return, on SYSTEM MINUS. Older units call that stud LOAD MINUS. The 500 A model uses M10 shunt bolts, tightened to a maximum 21 Nm. Follow the basic connections in the manual.
The editable example includes a placeholder bank, separate charging and load allowances, and a negative bus. Its short bank-to-shunt and shunt-to-bus links carry the connected system's current. They are not a recommendation for a fully loaded 500 A installation. If you use a Lynx Distributor, its negative rail belongs on this same system side.
Yes: its electronics need the supplied red Vbatt+ lead with a 1 A slow-blow fuse, connected to battery positive. That small supply fuse does not protect the main battery cables. The example draws this lead separately and retains its supplied length; it does not calculate a replacement sense-wire size. Verify main protection with the LiFePO₄ fuse tool.
Aux can monitor a second battery's voltage, midpoint voltage or temperature with the appropriate wiring. Aux and VE.Direct are outside this example. Follow the manual before using either.
Trace every negative return: a load or charger connected directly to battery negative bypasses the measurement. Reversed shunt connections can reverse the displayed charge/discharge sign. Also check monitor configuration and state-of-charge synchronization; the manufacturer troubleshooting guide separates connection faults from settings issues.
For a battery upgrade, continue with the lead-acid to LiFePO₄ conversion guide and the Orion XS charging example. All charging returns must remain on the system side when you expand this starter.
The boat wiring demo includes a SmartShunt in the house-bank return. The campervan wiring examples provide starting circuits to extend with monitoring; their returns must be rerouted through the added shunt.
Build it out
Add SmartShunt 500A/50mV (IP21) to your diagram, then connect your batteries, chargers and loads. Crimp calculates cable sizes and checks the connections as you draw.
Every cable you draw there is sized against ABYC E-11, from the same tables as the reference on this page.
Technical reference
Check the model, ratings and connection points against your own unit before choosing installation hardware.
The 500 A rating is the shunt's measuring range. Main cable sizes depend on the connected equipment, current and cable lengths; the measuring range does not select a cable or fuse.
Check stud sizes, fuse type, run length and how warm the space gets against the gear you actually have before you order.
BATT − is BATTERY MINUS; LOAD − represents SYSTEM MINUS, labeled LOAD MINUS on older units. B+ sense represents Vbatt+, powered by the supplied 1 A fused lead. Aux and VE.Direct are not modeled. The 500 A rating is the measuring range, not a fuse recommendation.
BATT −
batt-neg
negative · input
LOAD −
load-neg
negative · output
B+ sense
vbat
signal · bidi
Method & provenance
Manufacturer specifications describe the equipment. Crimp calculates cable results from the circuit and assumptions you enter.
From the maker
Manufacturer, model, ratings and which terminal does what come from the catalog. A newer revision, or the nameplate on the unit in your hand, can say something different — when it does, the nameplate wins.
ABYC E-11
Sized against ABYC E-11. Boats built to UK or EU rules answer to ISO 13297 — check these figures against it before you build. The run length and the current above are what drive the result. Crimp doesn't know how warm your space gets; draw the cable inside an engine-bay zone on the canvas and it sizes for the heat.
Next step
Open this example as a new project. Add your equipment and cable lengths, then review the sizing and checks for your setup.